Control system for hydraulic dredges



Feb. 8, 1949. P. J. CUSHING ET AL CONTROL SYSTEM FOR HYDRAULIC DREDGES Filed Dec. 29; 1945 7 Sheets-Sheet '1 INVENTbRS PAUL J. CU5H/N6 PAUL M. ENE/6H 7' Feb. 8, 1949. P," J. CUSHING ET AL 2,461,311

CONTROL SYSTEM FOR HYDRAULIC DREDGES '7 Sheets-Sheet 2 Filed Dec. 29; 1945 I} FIG. 2

- INVENTORS P404 J. CUSH/A/G P404 M. ENE/6H7 ATTOANEYS Feb. 8, 1949. P. J. CUSHING ET AL 2,461,311

CONTROL SYSTEM FOR HYDRAULIC DREDGES Filed Dec. 29, 1945 7 Sheets-Sheet 3 7 a4" (s21 /6 w w I30 I 62 P401. J CI'ZVEIIIYTORE 5 we F76. 4 v BY mmmz-we/a/vr ATTORNEY;

P. J. CUSHING ET AL CONTROL SYSTEM FOR HYDRAULIC DREDGES Feb. 8, 1949.

7 Sheets-Sheet 5 Filed Dec. 29, 1945 INVENTORS PAULJCUSH/N BY PAUL MEA/E//fl' ATTORNEXS Feb ,1949. P. J. C-USHING ET AL 2,461,311

.CONTROL SYSTEM FOR HYDRAULIC DREDGES Filed Dec. 29, 1945. 'I-SheetS -Sheet 7 IN VEN TORS PAUL J CUSH/A/G PAUL M. ENE/6H7- A TTORNEYS Patented Feb. 8, 1949 2,461,311 eQNTRoL SYSTEM FOBHYDRAULIC :mmnees P951111 J. cashing, Piedmont, and Paul M. Emi iit fibn of Delaware ydraulic Dredge Galii, a emera- A iieati'nn Deeemi'rier 29, 1945, Serial No. 637.,946'

'cfai mse (01. 114-230) Tide inventioh reletestohydraulic dredges, arid mere partibulfe'fly' to" means foi accurately poeitidnirig at hydraulicdredge for deep water Opera'- tiori. V

A n'ormai opereiting depth of a p'onventioigial hydraulic dredge is approximately fqz 'ty-five ieet bexiea'th the surfaee'of the 'wa'ter. When operating at these d'exjths'; it i'sctistomery tdQri'eI'Itate tlie dfedge inirelatioh to'theitpoi'tion of the Waterbedto' be dredged andto' move the dredge along ifi definite 'rei'eitioii thereto hy the utilization of a pair of sends, vertically movable anchor posts iiicated' at the of the dredge' aiid adapted to be extended downw may i'Iito the'Wa-te'r bed. '(fin'e spud is used as'eipivbt while dredging, the other spud"' being used 'to 'stepth'e dredge forwardly;

I Often the water is too deep 'O1Y rough to'penii it theuse ofspii'ds, and, oi'i these occasions, the diedge is pdsitioned'by wires; Three 'su'ch wires are used; one i'eadii'i'gal'sternof the" dredge and the other two'leadingtoeaiehside or quaTter -of the dredge, a nd eeich' wire'lead's fio'm' an arichdr to a cor'rimoii point gt the stein and from thence to wii'rch diimis'; menthese wires'eie taut; the dredge is held 111- pdsitipii for di ing. As eaeh 'set -up'or 'riosit'i'o ning of the dredge for a, specific 2 7 measure of mbveifxieiit of eacri'vfir'e in" order to step 'tiiedreige ah'eudecipufateiy with fes pect to disteme d'ireejtiiin; it is ir'ite'ride'd that a remoteeignalling lieiiitie, giirii'ig the eke'ct imbveme ia of each. file, sheiil he so pieced as to be wide? 'thecdnvefiient"siiiveillfinee 0f the levern'iai'i at the control st'atidrl v V v Six self-synchroniziflg"motors sire used, a pair for each df thethifeevifires; One m'oto'r of each pe il; the t 'enem'ifitefl is "Installed on a spring ioeded platform with a[ rtibheietiied Wheel of predetermiri'e'd diameterfii i'btiiiried on the shaft of 7 said riietor. The Wheel fricti'orialiy engages one of thethree Wires end is turned by it with no eitt'efidarit seepage b e t'w'ei i the: 'wiieelIe' hd wire. For earflrl unit of" mbvehieiit o'f the iv'ii'e; 'thewheel makes a predetermined u'riit' of ehg'dlarrotation.

oiieraitio'n 'i's' cbnipiete'd, the 'c'ii'ed'ge is steeped. forweirdly y peymgeut the required diet'ance on iiii' sti'n 'w'iie'aiidt'eiking ilf an'eqiiekl disfarrice (in each quarter wire.

It Has beeI-i'thepi actice'to station a winc'hm'an at the dime to mak'e the set-1113s uponrec'e'ipt of si g'i'reqi mm the levemiz-n'or dredge pofsit'i'onfer. Because of the equation" involved, this method-ne'eesserfly Iea' d's to ai deitainamotmt of eOnf-tisioifih'the relayitigof's'igi'iai's'; and, at best,

resuiia's'i t-l ieu'se of 'tworrie'ri for-the positioiiing oriei" ien'of thedredg'e.

ihstent in ention nialkes' if; ossible for 1 one 6; en 0' execute i'ii'i-e'p'o'sicidriiiigcipereitibiri,v and to dbeo' itr-amere etec-uratemdnrrer'than theconventienai' met'hdd;

Theimpi evedmethod of operation made Dos 's'ibie 5y said-insiiant invention util-i'zsthzeviinch drums; one for e'aeh 6f the three Conventional mrire's. 'The lecat ioh ofthese" d'rms on 'fhe'die'd'g'e is unimportant as lodges theyei'e pds'itioned" so that the wires can be Ted to them aiidflie hrikes Since: it is' impdssible" ti) plat ie the three drums where the ie've'rman cin s'ee'theiri-weil enough to measure" the input arid-output 6f" the Wife's merefroiii; and sincet'he iei ei'inan niiistfkiidw the ekeict The other m-btbf inea ch pair, receiver, is nrioiiiitied at the ebhtidl "station and the sheift of said meter 'fGHdV/' he movement df thesheift Of the 'treifi'smittei" motor eketctlyz The receiver gametes, throiig-h" a" gear reduction two hands on a dial marked to reed in feet andtehs of feet fromzidtboiiehiihdfedi.

With'the'thr'e dials 1h; frofit' of mm; the'leverdiam" conti'ol" arid knowledge-of the move ments ofthe thre'ifii object of the iriiieri'tioii; the'ie fore, is to provi'de a system-rev eehtieli'zedpo's'itioniri'g control of e'hydi'aiiliedi'ede. A

' Another object of the invention is to pijbvide a e ystei'ii fox- 0" tei5 "coiitio1iii1g the d-peiating position (if a, y radi'ic rediee frdm 'the colit'idlstatio'n e'i s defeug V I Stiii a f her'efifiebt -of' the inventiofi is' to provide :1 single station eontrol system" f0i*'viire'- Held 'I-iifdi'iiflic" d' I esiieff that one ifidii idual can iiievethe a ee" to a-- predetezfmiried roe-atiori Withinli t arid sirhifltafle'dds'iy" mumm deterr'nirie whether the eesirea pesmomne has Aiid yet renew object-=01 ei'e invention is! o 'pi'evide a ceiitrhiiz edicontfdl seamen" for awirecontrol "system io'r ehhydreuliii d dge afdaptedto be positioried by e' wire two'qde'rterwires, port wireende staihmlid w'ireleaiding from each side of the prow of the dredge, each wire having an anchor at the end thereof and being adapted to be moved over a winch-drum to lengthen or foreshorten the wire and position the dredge in any manner, and each wire having means associated therewith to provide for the accurate determination of the movement of said wire at the control station of the dredge.

And still a further object of the invention is to provide a method of relatively positioning a plurality of sheaves located on the stern of the dredge, each sheave being adapted to have passed thereover one of three wires used to position the stern of the dredge about a point, said method being calculated to provide for ready accessibility of the sheaves and wires for repair work thereon without the necessity of discontinuing the operational use of all of said sheaves and wires.

And yet another object of the invention is to provide a method of, relatively positioning the three sheaves on the stern of the dredge adapted to have passed thereover the three wires used to position the stern of the dredge about a point, said method being adapted to provide for a minimum of strain on the three wires when the prow f the dredge is moved laterally.

Otherobjects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings forming part of this specification, andin which:

Figure 1 is a view in elevation of a hydraulic dredge; V

Figure 2 is a plan view of the hydraulic dredge;

Figure 3 is a view in elevation of the sheave and wire assembly at the stern of the dredge;

Figure 4 is a side elevation view of Figure 3;

Figure 5 is a view along lines 5-5 of Figure 3;

Figure 6 is a view along lines 6-6 of Figure 3;

Figure 7 is a sectional view in elevation of one of the stern wires and its attendant transmitter unit; a

Figure 8 is a plan view of Figure 7;

Figure 9 is a view in perspective, partly broken away, of the control station of the dredge and the control mechanism therein;

Figure 10 is a view in elevation of a receiver motor for one of the three stern positioning wires showing a section of the dial system connected thereto; r I I Figure 11 is a left side view in elevation of a portion of the dial face of Figure 10;

Figure 12 is a view in elevation-of the control station showing one of the control wires for lateral movement of the prow of the dredge;

Figure 13 is a view in section of a sheave and dial for the control wire of Figure 12;

Figure l4'is a view in elevation of the dial of Figure 13; a

Figure 15 is a schematic diagram of the connections for a self-synchronizing transmitter mo.- tor and a, self-synchronizing receiving motor;

Figure 16 is a schematic diagram of exaggerated size showing the preferred relative location of the stern sheaves and the resultant pivoting thereof when the prow of the dredge, shown in shadow outline, is moved laterally; and

Figure 17 is a schematic diagram, similar to Figure 16, showing a conventional method of relatively locating the stern sheaves.

Referring to the drawings for more specific details of the invention, l 9 indicates generally-a hydraulic dredge having a hull [2, a superstructure M, a deck is on the .upper' surface. of the superstructure, and a control station I 8 secured to deck 16. A cantilever boom 20 having one end pivotally mounted in a manner, not shown, to the hull I2 is braced against angular movement by cables 22 secured at each side of the upper end of the boom 20, said cables being guided and supported by a trussed tower 24 supported on deck i6 and being anchored on the after portion of deck Hi in any conventional manner.

A digging ladder 26 mounted on trunnions 28 on ,the hull l2 has at the extreme end thereof a cutting head 30 adapted to be rotated by a cutting head shaft 32 supported on the ladder 26 by a plurality of bearing 34, said shaft being adapted to be driven by a motor 34 supported on the ladder 26. The ladder 26 has attached thereto a cable 36 supported by one end of a block pulley 38, and a cable 48 supporting the sheave of the block pulley 38 passes over a sheave 42 mounted for rotation in the upper end of the cantilever boom 20 and from thence to a winch drum 44, having brake and clutch controls, not shown, supported on the hulllt within the superstructure 14. The lengthening or foreshortening of the cable by the winch drum 44 is effective to raise or lower the digging ladder 26.

Winch drums 45 and 48, supported for rotation on the hull it within the superstructure l4 and having brake and clutch "controls, .not shown, have cables '58 and 52, respectively, connected thereto, said cables passing over sheaves 54 and 56 mounted for rotation on opposite sides of the lower portion of the cantilever .boom 29. The cablesiil and 52 extend from the sheaves 54 and 56 over sheaves 58 and 60 mounted for rotation on opposite sides of the digging ladder 26 to anchors, not shown, oppositely disposed with respect to said ladder.

Attached to a fixed arm 62 on the digging ladder 28 is a, wire 64, and said wire passes over a plurality ofsmall sheaves to a large sheave 55 keyed to a shaft 66 supported for rotation in a wall of the control station l8. The wire 64 makes a 360 degree turn on sheave 65 and passes over a plurality of sheaves to a well 6! in the tower 24 where said cable is attached to a weight 68. A stationary indicating dial mounted on bearings as shown (see Figure 13) has on the face thereof a plurality of indices 12, and a movable indicating arm T4 fastened on the end of shaftfifi to rotate therewith is adapted to move concomitantly with the moving .of wire 64, upon the raising or lowering of the digging ladder 26 by movement of the cables 40 and 36, to indicate on the calibrated dial 19 the operating depth of the cutter head 30.

Awinch drum 76, mounted for rotation substantially amidship and having brake and clutch mechanism, not shown, has connected thereto a cable is passing upwardly and rearwardly therefrom over a sheave BB and through a housing 82. The cable 78 extends substantially the length of deck 16 to'pass over a sheave 84 mounted for rotation on the edge of the deck; The cable 18 then extends from sheave 84 to sheave 86, mounted for -degree traverse in'lug 88, and from' thence to a stern anchor, not shown. Lugs 88 are bolted to a frame member 90, secured, as by bolts, to the end of the hull 12.

Winch drums 92 and 94, similar to drum i6 and located adiacently thereto, have connected thereto, respectively, cables 96 and 98, said cables passing rearwardly and upwardly over guide sheaves I00 and 32, through housing 1G4, and rearwardly along the deck 16 .to sheaves-I98 and H38 mounted for independent rotation on shaft I I0, said sheaves being mounted substan- "commonly known as sleeves I26 and I28 secured to the hull I2. The cables 86 and 98' pass over pivotable sheaves I38 and I32, respectively, mounted on an extension member I34 of the spud Well H6 and adapted to have a traverse of 180 degrees.

are attached to anchors, not shown, It will be noted and 6 that the substantially equidistant from the axes of quarter sheaves I32 and I32; Since the purpose of the two anchored quarter the stern line I8 is to position the stern of the and sheaves carried by spud well II6.

A housing 82, secured to the deck I 6 and through which cable 78 passes, houses one of three similar units, the other two being contained in housing I04. For purposes of disclosure, a description of one of the three similar units will suffice for the three.

The housing 82, connected as by bolts to the deck I6, contains therein a plate Me hinged to support members I42 connected to the deck I G. Bolts I44 connected to the deck I6 pass through the other end of the plate I46, and said end of the plate I40 is yieldingly urged toward the deck I6 by springs I46 held in I48 threaded n the bolts rotation on the plate I49 by bearings I 58 mounted on said plate is a shaft I52 of the self-synchronizingmotor I54 also mounted on plate I40.

The shaft I 52 has keyed thereon a wheel I 55 haVing a rubber-covered periphery I58, extend- I44. Supported for the wheel I56 and consequent rotation of the shaft I52 supporting the wheel. Since the wheel I55 is of a predetermined diameter, the movepair of transmitter-receiver motors used in corn.

Figure 10. These motors are Selsyn motors, the word Selsyn being the trade mark name of motors of this type manufactured and sold by the Gen tension .by wing nuts and having keyed at the control station eral Electric Company of Schenectady'New York; Standard units of this type have their rotors Wound with stators have a rotor has leads I a single phase excitation source I 64; the same source to which the leads of the rotor I58 of the transmitter motor I54 are connected. Each element of the three-element Y-connected winding of the stator I72 of the transmitter motor I54 is connected to a similar element of the threeelement Y-connected winding'of the stator I'M of the receiver motor its by leads I16; I18', and I80.

the shaft I52 of the generator I54 caused by any movement of the wire 18 in engagement with the wheel I is duplicated by a shaft I82 connected to the rotor of receiver motor I56} Shaft I82 extends into a housing I84 and is supported for rotation therein by bearings, as shown in Figure 10, said shaft being'sleeved on and keyed to a shaft I86 having a clutch flange I88 adapted to be yieldingly urged, as by spring I90, into engagement with another clutch flange I92 on a sleeve I94 keyed to shaft I86. The sleeve I94 is supported for rotation by bearings as shown, and said sleeve carries a gear wheel I96 adapted to a large gear wheel I98 adapted to mesh with a gear wheel 2I2 keyed on a shaft 2| 4 supported for rotation by bearings of shaft I 86 is movable into the housing I84 against 2I6. A portion 2l8 wardly with respect the springl fl to disengage the clutch flange I88 from the clutch flange I52; and thus prevent the transmission of movement between'shaft I82 and gear I96 on sleeve I94 When this is done} a knob 2211 on shaft 2! may be manually turned to reset the indicating pointers 202 and 2I6 to the zero position on a dial face 222 having a plurality of ind'ices 224, said dial 'face being located on the face of the housing I84.

Figures) illustrates a portion of the interiorof I 8 showing the location or indicating dial- 222, one of three such dial'sf'the one end an indicating pointer tolateral movement. The

218-, one pair'oti-eaoh six pairs oi-said levers'being adapted to operateone of the six winch drums hereinahovedescribed. I Dne lever in each pair isfor. actuating a: clutch- .to move the drum forwardly to reel the wire, and the remaining lever is used for controlling a-bpake to regulate the payingv out of the wire or to hold the drum against any movement whatever.

For the purpose of describing. the operation of the dredge and the control system: thereof, the dredge will be assumed tobe in the operating position shown in-Figure 1. The anchoring of the stern wire 1:8 and the quarter wires 95 and 98 serve to establish a vertical line pivot for the stern of the-dredge, while: the anchoring of the lines: 50 and 52 on the starboard. and port sides of the dredge serve to fix the dredge with respect leverman in the controlstation I 8. knows-the operating depth of the cutter head 30, since the cable 64, the sheave S5 and the pointer 14. indicateusaid posit-ion to. the lever-man on the dialiace- HI. The motor 34 is then actuated to drive the'cutter head ,.and, as the work is done by the cutter head, digging ladder 26 ismade to describe an arc to follow the 1 work by pivoting the dredge through a shortenmg of one of the lines or 52 caused by the leverman actuating an appropriate lever 228 to drive. one of the winch drums A6 or 48 in the reverse direction. gouged from the waterbed.

The dredge I0 and the digging ladder 26 are concomitantlypivoted-by lengthening or shortening: thewires 5d and 52. When a complete arelike necessary to stepthe dredge forwardly to prepare for the next cut; l his is done by rotating the winch drum. FIB: in the reverse. direction to pay out. a: predetermined amountof cable 18,, said amount being indicated pointers .2 IiZ-and -2:I 6-- on: indicating. dial 222. The movement' of the cable causes rotation of the wheel Ito-in the housing 82 and consequent rotation ofisha-ft I52, the rotor shaitof transmitter motor L54; shaft I52 is.- duplicatedby a similar amount of rotation-oi rotorshait I82 or receiver motor I55, said motion being translated through appropriate transmitter-receiver wiring connections, as schematically shownin Figure 15.- rotation of shaft I86,- clutch flange I88, clutch flange 18-2; gear I96, gear wheel I98, and sleeve Motoceuse movement of the indicating pointer 202 toind-icatethe smaller units of measurement of the-movement ofwire Id. The sleeve: 2M: and gear wheel 19d causes the rotation ofgear 2M,- gear: wheel 2105, shaft 208,.gear 21 0, gearwheel 242;, and-shaft. 2 M to cause a. movement of the indicating pointer 216. to. measure tnelarger units ormovement of wire 18.

list-he wire 18 ispa'd out, quarter wires 96. and More takenu-p equally by forward movement of the: winch drums 92: and. 94,. respectively; This toreshortening of wires 9 .6 and 98 serve tostep thev dredge forwardly a predetermined amount, said amount being indicated. on dials. similar to dials 222, locatedin the controlstation 18; since each of the-wires-ofi and 98 have atransmitterreceiver motor: pairs, similar to. motors I54: and I-SB-iorwire 18, to accurately transmit theamount of-movementof. said wires on the indicating dials withinthe control station It.

When the leverman is satisfied from examination or the dial- 222 that. the: dredge is-:position for the next cut,- he halts: themovement of the Thus an arc-like path is 1 cuthasbeenmade in the. water bed, it is to the leverman by The amount of rotation of'the rotor Shaft I82 causes rotation of L of being'pulled'loose from V 8 winch drums 16, 92- and- 94 by use 01 the appropriate levers 22-8., position, shown in dredging cut.

lt will be appreciated that all the levers and dials necessary for the complete operation of the dredge and accurate positioning thereof are all centrally located in the. control, station I8 where they may be under the surveillance of one man.

Figure 16 is a relative positioning of the pivot point of sheaves S5, I-Sil, and, I32 located on the stern oi Figure 1:, to begin another the dredge and used in coniunction with wl'resiTB,

9.6, and 98, respectively.

stern sheave system. The three stern position ing wires I8, 96, and 98, as well as the two. wires 59 and 52 used to position the bow of the dredge in making. a dredging cut anchored, and the pivot points of sheaves 86;. I311, and 32 are shown to constitute roughly an equilateral triangle. In following a dredging cut, the bow, as herein-above described; is swung either port or starboard by the shortening or lengthening of wires 58 or 52, the wires 18, 9'5, and BBno't being used in this bow swinging operation. For purposes of illustration, let us assume that the bow is pivoted to the left, as-viewed in Figure 16, by a shortening of wire 52. As this. occurs, the pivot points of sheaves 86, I30, and I32 swing with the dredge to describe an arcing movement to assume the position shown at 86"; I30; and !32. This movement causes a slight slackening in the wire '58, since this wire assumes the, new position of i8, hich is slightly shorter than 13. Similarly, the wire 98, in its new position 98",

The third wire 95 is put under tension to assume the position 95' where it is longer than in its original position, a catenary slack in wire95 havingbohn the lengthening process. it will beseen that two of the three stern positioning wires are slaclcened and the third is tightened upon-the pivoting oi the dredge how. This method of locating the pivot points of the three stern sheaves results in a minimization of the danger of dragging anyoi the three stern anchors or the snapping of any of the'wires through undue tension being applied thereto and is the method oi sheave pivot location used in this invention.

As contrasted with the method of pivot location shown in Figure 16, Figure 1'-l'- illustrates a conventional manner-oi locating-the sheave pivot onthestern of the dredge. In Figure 17 the piv- 'ot point of sheave is located astern of the pivot points of sheaves I3fl and I32. Assuming a similar bow pivoting operation as outlined hereinabove for Figure 16, the pivoting: points 86, I36 and 52-2 describe arcing movements to reach new positions 86, 33, and I132. As these pivot points move. through the pivoting movement-oi the dredge, wires I8, 96, and 98 assume-the new positions I8, 96', and 98'. It will be seen from an examination of Figure 17 that 98" islonger than 98, is longer than 86', and 18- is longer than I3. Thus, all three stern positioningwires have become tightened, and the danger of the wires snapping or the anchors on the-'ends-theretheir positions on the water bed is ever present.

It can be demonstrated that if the sides of an imaginary equilateral triangle joining the pivot points of the three stern sheaves are as The dredge is again inthe are shown to be.

much, asten inches in:l ngthn elvivotingzef th bow of a conventional-sized dredge operating on conventional sized Wireszis s-ufiicient itossnap these-wires when the, piyotpoints of the stern sheaves are locatedlin amanner similar toFigure 17. The manner of locating the sheave pivot points in the instanteinvention, as demonstrated in Figure 16;, has, therefore, readily apparent advantages over the manner of locating the sheave pivot points inl 'igure @137.

The location of sheave 86 above the water level, as contrasted with a conventionallocation of all three stern sheaves beneath the water level, ofiers certain advantages. If the lines leading from the under water sheaves, or the sheaves themselvesbecome fouled in operation they-can be raised above the water .leveli'or repair .by pivoting thespud well lit. When this isneoessalty, wire l8 at the stern of the dredge and wires 50 and 52 at the bow of the dredge may be kept in their anchored positionltoimaintain the dredge in the position it held before the under water sheaves were raised-.- A conventional method of locating all three stern sheaves under water necessitates the iraisingofv all, three, since-they v are generally located in a single well, in case of the necessity for repair work. When such an occasion for repair work occurs, the dredge is held by wires 58 and 52 only and is free to swing with the current or the wind. Much time must be spent in relocating the dredging out after the repair work is finished.

While the preferred embodiment of the invention has been shown and described, it is understood that modifications in the invention may be made within the spirit of the invention and the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent is:

1. On a hydraulic dredge having a control station, a plurality of mooring wires adapted to position the vessel for dredging operation, and means i.cluding control devices located at said control station for retracting or lengthening each wire, an electrical signalling device for each wire comprising a self-synchronizing transmitter motor having a rotor shaft adapted to be rotated by a movement of the wire, a self-synchronizing receiver motor, a plurality of wire leads connected to the motor so that the rotor of the receiver motor is adapted to reproduce the movement of the rotor of the transmitter motor, a dial for each wire at the control station, each dial having indicating means associated therewith and connected to the rotor shaft of a receiver motor to indicate the direction of movement and magnitude of said movement of one of the mooring wires.

2. On a hydraulic dredge having a control station, a plurality of mooring wires adapted to position the vessel for dredging operation, and means including control devices located at said control station for retracting or lengthening each wire, an electrical signalling device for each wire comprising a self-synchronizing transmitter motor having a rotor shaft, a wheel mounted on the rotor shaft in frictional engagement with the wire, said Wheel and rotor shaft being adapted to be rotated by a movement of the wire, a self-v synchronizing receiver motor having a rotor shaft, a plurality of wire leads connecting the motor so that the rotor of the receiver motor is adapted to reproduce the movement ofthe rotor of the transmitter motor, a dial for each mooring wire at the control station, each dial having respective anchor r Wires 'passineover said. sheaves .is-shortened upon sideward movem ntor the bow-of; the dredge nd e sionine oisaia wiresis avo ded-j ing wireand a pair o q r moorin wires. l ad n from the s ern of t e e ge. a sheave for; each-wire at its point of departure irorn the dred e, a subst nt ally v rtical pivot for each sheave, said'pi-Yots. for the quarter wire sheaves being substantially equidistant from th bow of; the dr e n spac dasubstantiallv equidistantly from the longitudinal axis of the dredge, and said pivot for the stern wire sheaves being located on a longitudinal axis of the dredge nearer the bow than the aforesaid pivots; whereby the distance between two of said pivots and the respective anchors for wires passing over said sheaves is shortened upon sideward movement of the bow of the dredge and tensioning of said wires is avoided.

5. On a hydraulic dredge having a stern mooring wire and a pair of quarter mooring wires leading from the stern of the dredge, a sheave for each wire at its point of departure from the dredge, said sheave for the stern wire being located above the level of the water and said sheaves for the quarter wires of necessity being located below the level of the water, a pivotfor each sheave, said pivots for the quarter wire I sheaves being located equidistantly from the bow of the dredge and spaced slightly apart, and said pivot for the stern wire sheave being located between the aforesaid pivots and closer to the bow of the dredge as viewed in a plan view of said dredge.

6. On ahydraulic dredge, a stern mooring wire, a sheave for said wire mounted on the stern of the dredge above the surface of thewater, a pair of quarter mooring wires, a sheave for each wire carried within a spud-well substantially below the surface of the water, said spud-well being adjacent the stern and pivotally supported by the stern, the relative location of the three sheaves being such that either the stern wire or the quarter wires may be rendered inoperative without the remaining wire or wires being rendered inoperative.

7. On a hydraulic dredge having a stern mooring wire and a pair of quarter mooring wires leading from the stern of the dredge, a spud-well depending from the stern of the dredge, a sheave for each quarter mooring wire located in the lower portion of the spud wheel beneath the surface of the water, a sheave for the stern quarter wire located on the stern of the dredge abovethe surface of the water, said spud-well being pivotally mounted on the dredge whereby said spud-well may be raised for repair or examination of the quarter mooring wires or sheavesthereof and whereby the stern mooring wire may be still operative,

shaft-oi the receiver motor of movement and magne hydra licdr dc havine a stern moor- 8. On a dredge having a stern mooring wire and a pair of quarter mooring wires leading from the stern of the dredge, means constituting a pivotal connection between each wire and said dredge at the point of departure of the wire from the dredge; the pivotal connection for the stern wire lying forward of the pivotal connections for the two quarter wires; whereby the distance between two of said pivotal connections and anchors for the respective wires is shortened upon sideward movement of the bow of the dredge and tensioning of said wires is avoided.

9. A stern mooring system for dredges comprising a pair of quarter wire sheaves mounted adjacent the stern of the dredge, quarter wires secured to the dredge and passing around said sheaves and forwardly with respect to the dredge, a stern sheave, a stern wire secured to the dredge and passing around said stern sheave and rearwardly with respect to the dredge, means whereby each of said wires may pivot in an efiectively horizontal plane with respect to the dredge; said pivot means being disposed so that the pivoting points of the quarter wires are laterally spaced substantially equidistantly from the longitudinal 12 axis of the dredge, and the pivoting point of the stern wire is forward of a line connecting the pivoting points of the quarter wires; whereby tensioning of said wires upon sideward movement of the bow of the dredge is avoided.

PAUL J. CUSHING. PAUL M. ENRIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTS 

